Bugging

Annoying or bothering someone repeatedly, or secretly placing a listening device to spy on conversations.

From 'bug' (noun), originally meaning an insect, which evolved to mean a small mechanical defect in the 1800s, particularly in Thomas Edison's lab. By the 1940s, 'bug' extended to mean a hidden microphone, and 'bugging' became the gerund form. The annoying sense likely derives from the idea of pestering insects.